Investigating the plasticity of Atlantic sturgeon Acipenser oxyrinchus migration timing in a changing climate

Atlantic sturgeon Acipenser oxyrinchus, a US federally listed endangered species, exhibits broad-scale movements between rivers and coastal environments while also periodically aggregating along the Atlantic coast. Despite a harvest moratorium enacted in 1996, there is little evidence of population recovery. This is largely attributed to the species’ conservative life history characteristics, but is exacerbated by incidental captures in fisheries and potentially by climate change. It is unknown what impacts climate change will have on long-lived species with localized genetic populations and an anadromous life history, including Atlantic sturgeon. To promote recovery, an understanding of their temporal and spatial habitat use is required. Movements of tagged Atlantic sturgeon have been monitored within the New York Bight through a network of passive acoustic receiver arrays resulting in 4 million detections of 718 individuals from 2010 to 2022. Acoustic data from the Rockaways, New York, were used to inform gradient boosting machine models to identify environmental drivers of migration and to investigate the impacts of climate change on the migration timing of Atlantic sturgeon. Photoperiod and water temperature were primary drivers, with photoperiod dictating arrivals and water temperature dictating departures from the Rockaways. Under warmer conditions, Atlantic sturgeon may arrive to and depart from the Rockaways 60 d earlier than previously observed; however, photoperiod may limit the plasticity of Atlantic sturgeon migration, potentially exposing them to suboptimal water temperatures within their photoperiod-dictated migration window, emphasizing the importance of considering photoperiod for understanding how species will respond to climate change.